Pulp stock agitation



sept. 7V, 1937.

J. A. ROSMAIT PULP STOCK AGITATION Filed May 5l, 1935 2 Sheets-Sheet l INVENTOR. c/ohn A Foomafz' BMV/2% l ATTORNEYS.

Sept. 7, 1937. J. A. RosMAlT PULP STOCK AGITATION Filed May 3l, 1935 2 Sheets-Sheet 2 INM/@m ATTORNEYS.

Patented Sept. 7, 1937 UNITED STATES PATENT OFFTCE 19 Claims.

This invention relates to paper manufacture and more particularly to an improved method and atpparatus for sto-ring and agitating paper pulp s oc In the manufacture of paper it is necessary at times to store the paper pulp stock in large storage tanks or chests. The pulp stock is mixed with a large amount of water, and if left unagitated will either settle to the bottom of the body of water or iioat to the top depending upon the type of pulp stock employed. This destroys the uniformity of the pulp stock mixture and results in poor and unpredictable grades of paper.

In the past attempts have been made to agitate vthe pulp stock stored in chests by means of paddle agitators. These devices were relatively expensive to install and operate, and only agitated that part of the pulp stock immediately adjacent thereto. Furthermore, a plurality of these paddle agitators were required to extend into the chest and this awkward construction plus the lubricationrequired upon the operating parts obstructed and contaminated the pulp stock.

Agitation of the contents of a pulp stock chest must be thorough and complete. If this is not provided or if the agitation is improperly furnished, dead deposits or immovable islands f pulp stock will form in the chest which not only take up storage space reducing the capacity of thcle chest but also sour and contaminate new pu p.

It is an object of this invention to provide a storage tank or chest for pulp stock or the like which provides a tho-rough and complete agita- -tion of the pulp stock. In accomplishing this object a circulatory system of improved design is associated with the chest and compels continuous movement of all of the pulp stock through the chest. i

Another object of this invention is to provide acirculatory system for the pulp stock which is inexpensive to install and operate and which does not require the presence of movable parts in the chest. A further object is to provide a storage chest of such a construction that there is no necessity for long floor pitches, midfeathers, or intermediate supports in the interior of the chest which would obstruct the free flow of the pulp stock, retard its circulation, and reduce the chest capacity for a given size chest.

A meritorious feature of the invention resides in the novel formation of a defiector or baiiie for directing the o-w of the pulp stock tov those areas in the chest where dead deposits of the stock are likely to form. Another meritorious feature resides in the improved manner of introducing new pulp stock which quickly mixes the same with the older stored stock.

The invention comprises essentially a large storage tank or chest through which pulp stock is continually passed in one direction and recirculated. A circulatory system is associated with the chest and is arranged to discharge pulp into one end of the chest and withdraw it from the other end thereby enabling the pulp stock to iiow uniformly inl one direction from one end to the other end of the chest. Positioned within the chest is a diverting baffle or deiiector which is adapted to direct the flow of pulp stock to those areas and corners of the chest where, if such deflector were not used, the pulp stock would be likely to deposit and clog the chest.

Beaters are associated with said chest and communicate therewith through conduits which empty into the circulatory system prior to reentrance of the stock into the contents oi' the chest. The circulatory system is provided with a by--pass for discharging fluid or stock upon the deiiector while the other end of the chest is being cleaned.

Other features and advantages of the invention will appear from the detailed description which will now be given in conjunction with the accompanying drawings, in which:

Figure 1 is a cross-sectional view showing the interior of the stock chest and the relation of the beaters to the chest,

Fig. 2 is a top interior View of the chest along line 2--2 in Fig. 1,

Fig. 3 is a View partly in cross-section showing a modification of the apparatus, and

Fig. 4 is a cross-sectional view along line 4-3 of Fig. 1.

A stock chest I0 for storing pulp stock is associated with a plurality of beaters l2 from which it receives pulp stock in the manner to be described hereinafter. The chest may be made of reinforced concrete construction as indicated in the drawings or of any suitable material. The chest may be cast as monolith extending from fioor level Il to floor level I3 thereabove. As i1- lustrated in the drawings the chest forms an actual part of the building. The chest is provided with a floor Ill sloping from one end of the chest to the other and a recess or depression I6 is formed in the floor adjacent to its lower end. The side and end walls of the chest round into the bottom or iioor of the chest as indicated in the drawings.

The apparatus for continuously circulating the pulp stock into and out of the chest will now be described. rIhis apparatus causes the pulp stock to flow uniformly in one direction through the chest from the higher end to the lower end of the chest. Maximum storage area for each given size of chest is provided by such procedure. There is no necessity for long iloor pitches, or midfeathers or intermediate supports. The pulp stock ilows uniformly and uninterruptedly from one end of the chest to the other.

A pump i8 is located outside the chest, and by means of the suction tube 2E] withdraws pulp stock from the recess i E5 to be forced by the pump through the discharge pipe 22. rllhis pipe in turn is connected to the reduced end of a mixing ow tube 2li which extends lengthwise through the chest to discharge at the opposite end of the chest. This tube gradually increases in diameter as it approaches its discharge end as is clearly apparent in the drawings. The chest proper, the suction tube 28, the pump discharge pipe 22 and the flow tube 26 form a circulatory system through which the pulp stock is constantly delivered. The continuous movement of the pulp stockthrough this system agitates the stock and prevents the formation of dead and immovable deposits of the stock within the chest. Motor 2t drives the pump, and valve means fi may be provided for controlling the volume of pulp stock circulated.

Depending from the tube 24 at the low end of the chest floor is a deflector or baiie 38 of :a generally V-shape configuration with the apex of the deilector facing into the flowing pulp stock. The angularly disposed sides 32 of the deflector dire-ct the iiow of pulp stock outwardly against the side walls of the chest at the low end of the chest. As shown in Fig. 1 the baiile slopes from top to bottom in the direction of stock flow and terminates within the recess l5. The sides 32 are of less width at the top and gradually increase in width as they approach the bottom. At the base of each side a slot or aperture t@ is formed for permitting a portion of the pulp stock to flow therethrough and into the region in the rear of the deector. The deector is constructed to t around the ow tube at its upper end. It is obvious that additional spreader or deflector means may be provided if desired. These may be positioned substantially along the longitudinal median line of the chest or to one side or the other to cause lateral divergence of the stock flow.

A spout or pipe it is arranged to by-pass pulp stock or fluid to flow through the tube ,2t

downward upon the sloping sides 32 of the deilector. Buttery valves S58 and are provided in the tube 24 and spout 35 respectively. These valves are coupled together by appropriate lever mechanism so that when one is closed the other is open. The manual control of these valves is indicated at 42. Normally valve il@ in the by-pass is closed, but when it is desired to flush and clean the interior of the tank the valves may be operated to by-pass the fluid contents of the tube 24 downward upon the inclined parts of the deilector.

The beaters l2 communicate with the chest it. The preferred manner of such communica- Vtion is by way of the flow tube 2. As shown in tents of the ilow tube 2@ a preliminary mixing is obtained before the stock is discharged into the tank.

By sloping the licor of the chest from one end to the other a hydraulic gradient in the direction of the ow of the stock is produced. The flow is unobstructed and in one direction. The diverting or deflecting device 30 is arranged to assist in the established law of flow through centrifugal or axial flow pumps in which the pump capacity increases with decreasedY head. The deflector is narrowest at the tcp and oiers less resistance to the flow of the stock at the higher levels. Being wider adjacent the bottom, it offers greater resistance and more thorough agitation by forcing the lower levels of the chest contents to pass further around before being withdrawn from the chest by the pump. The delector or balile is located at substantially the point of highest velocity of flow, and the stock instead of flowing` at this point of highestvelocity'into the pump suction, it is diverted around the delector before it can enter the suction tube thereby pulling on the stock and forcing it to split its iiow lines around and under the deilector and thence into the pump suction.

The discharge or flow tube 2li is constructed with an increasing area from inlet to outlet and serves to reduce the total pumping head as Well as permit the stock to roll over and over in its course through the ow tube. When the pulp stock discharges from the flow tube it spreads out and piles up to create a head and furnish the hydraulic gradient for the ilow of the stock down the chest toward the pump suction. The

pump should be of a type to handle a large Volume at a very low discharge head.

When it is desired to wash out the chest, the'- by-pass is regulated to direct the discharge of the pulp stock upon the baffle where'it flows down the inside and is contained in the lower part of the chest. This allows the upper Vend of the chest or about of it lto be washed and cleaned while the stock from the lowest end of the chest circulated through the Vby-pass is pumped out and used up in the nextV operation.

- In the modication illustrated in Fig. 3 there is shown a stock lter 50 lwhich delivers stock in a continuous stream into one end of the chest. It is removed from the other end of the chest by a pump and recirculated through tube 24 in the same manner as described above.

What I claim is:

1. The method of delivering pulp stock to a storage chest and agitating the same therein which comprises pumping the pulp from a low partV of the storage chest and reintroducing it into the chest at a high partV thereof to establish 4 a circulatory system including the chest asa part thereof, and delivering additional pulp stock into the circulatory system prior to the reintroductio-n of the stock into the chest.

2. A storage chest for pulp stock and apparatus l drawing pulp stock from the lower levels of theV chest and delivering the same to the flow pipe to be discharged thereby into the chest, a deflector extending downwardly from the fiow pipe intermediate' the ends of the chest, and valve means for by-passing the contents of the flow tube downward upon said deflector.

3. In combination with a storage chest for pulp stock, a tube extending into the chest and adapted to convey pulp stock therethrough and discharge the same into the chest, a deflector in said chest, and means for withdrawing pulp stock owing through said tube before it reaches said discharge and directing the same upon said deilector.

4;. ln the manufacture of pulp stock, a storage chest, flow tube disposed along the upper level of said chest, means for circulating the pulp stock in said storage chest through said flow tube, a plurality of beaters associated with said chest, and means for emptying the contents of said beat-ers into said flow tube to mix the same with the pulp stock flowing through the tube prior to its discharge into the tank.

5. ln a storage chest for pulp stock, a deflector disposed angularly to the flow of the pulp stock through said chest, said deflector having an aperture adjacent its lower extremity through which a portion of the pulp stock may flow to prevent the collection of non-flowing pulp stock behind the deilector.

6. In the manufacture of paper pulp, a storage chest having inclined bottom from one end thereof to the other, said bottom provided with a recess adjacent the lower end of the chest, means for discharging pulp stock into the chest at the higher end of the chest, means for withdrawing pulp stock from said recess the lower end of the chest thereby creating a continuous flow of pulp stock from the higher end to the lower end of the chest, and a deiiector located adjacent said recess and arranged to divert the flowing pulp stock outwardly around the same and toward the corners of the chest prior to its withdrawal from the chest.

7. In the manufacture of paper pulp, a storage chest for pulp stock having a sloping bottom extending from a higher level at one end of the chest to a lower level at the other end of the chest, a tube disposed adjacent the top of said chest having its discharge end terminating adjacent the higher end of the chest, means for withdrawing pulp stock from the lower end of the chest and delivering the same to said tube to be discharged t erefrom into the chest, a deilector positioned in said chest for diverting the ow of the stock through said chest into those areas where dead deposits of stock may form, means for bypassing the fluid contents of said tube upon said deilector, and means for introducnew pulp stock into said tube.

Apparatus for storing and agitating pulp stock comprising, in combination, an elongate chest having a bottom sloping from one end to the other, a flow tube disposed in the upper level of the chest having its discharge end terminating abovethe higher end the sloping bottom, means for withdrawing pulp stock from the lower end of the chest and reintroducing it into the chest through said flow tube to provide a continuous flow of pulp stock through the chest from the higher end to the lower end, a V-shaped deilector mounted vertically in the chest spaced from the side walls thereof, said deector having its apex facing into the flow of pulp stock splitting the flow laterally toward the side Walls of the chest to prevent the formation of dead areas of pulp stock in the chest.

9. Apparatus for storing agitating pulp stock comprising, in combination, a chest having a sloping bottom tending to drain the pulp stock contents toward one end thereof, means for withdrawing pulp stock from the lower end of the chest and reintroducing the same intov the chest at the other end providing a continuous unidirectional flow of pulp stock through the chest, a V-shaped deector mounted vertically in said chest with the apex thereof facing into the flow of pulp stock, said deector being of increasing width from the top to the bottom thereby offering greater resistance to the flow of stock and consequently causing greater deflection of the stock in the lower levels of the chest.

1G. Apparatus for storing and agitating pulp stock comprising, in combination, a chest, means for flowing pulp stock through said chest, a V- shaped deiiector mounted vertically in said chest between the side walls thereof having its apex facing into the flowing pulp stock, said deector being wider adjacent the bottom of the chest and extending in closer proximity to the side walls of the chest to cause a greater divergence of that portion of the pulp stock flowing in the lower levels of the chest.

ll. In the manufacture of pulp stock, a storage chest, a flow tube disposed along the upper level of the chest having its discharge end terminating adjacent one end of the chest, means for withdrawing pulp stock from the other end of said chest and returning the same to the chest through said flow tube, means for introducing new pulp stock into said flow tube, said flow tube being of increasing diameter as the discharge end is approached to cause the new and the old pulp stock to roll over and over together in their course through the tube providing a preliminary mixing of the new stock with the old well agitated stock prior to its introduction l proached to cause the pulp stock to roll over and over upon itself in its course through the tube whereby a thorough mixing of the stock is provided.

13. Apparatus for storing and agitating pulp stock comprising, in combination, a storage chest, a pump having an intake communicating with the bottom of the chest to withdraw pulp stock therefrom and having a discharge communicating with the top of the chest to deliver pulp stock thereinto, said pulp discharge being of increased area as it approaches its outlet, and means for delivering additional pulp stock into that portion of the pulp discharge of increasing area to mix with the pulp stock flowing therethrough prior to discharge into the chest.

le. Apparatus for storing and agitating pulp stock comprising, in combination, a storage chest, a pump having an intake communicating with the bottom of the chest to withdraw pulp stock therefrom and having a discharge communicating with the top of the chest to deliver pulp stock thereinto, said discharge being provided with a flaring portion of increased diameter adjacent the discharge end thereof, and means for delivering additional pulp stock into said flaring portion of increased diameter through delivery conduits of substantially reduced diameter as compared with the diameter of the flaring portion.

15. Apparatus for storing and agitating pulp stock comprising, in combination, a storage chest, a pump having an intake communicating With the bottom of the chest to Withdraw pulp stock therefrom and having a discharge communicating With the top of the chest to deliver pulp stock thereinto, a baille disposed Within the chest-adjacent to the pump intake adapted to Acause the pulpl stock flowing through the chest to sp-read outwardly toward the side walls of the chest before entering said pump intake.-

16. Apparatus for storing and agitating pulp stock comprising, in combination, a chest for storing pulp stock, a circulatory system for withdrawing pulp stock from a lowlevel Within the chest and discharging the pulp stock so Withdrawn, into a high level Within the chest including a discharge tube having an increased diameter adjacent its discharge outlet, and means for delivering additional pulp stock into Vsaid tube for mixture with the circulated pulp stock flowing therethrough prior to the discharge of the same into the higher level of the chest.

17. Apparatus for storing and agitating pulp stock vcomprising a storage chest for pulp stock, pump mechanism communicating with a low part of the chest to Withdraw pulp stock therefrom and with a high part of the chest to deliver said WithdraWn pulp stock thereto to establish a circulation of pulp stock through the chest, a sloping baille Within the chest shielding the outlet to said pump and adapted to direct the pulp stock flow through the chest toward the side Walls of the chest, and means for by-passing a portion of the pulp stock Withdrawn from the chest by the pump and discharging the same directly upon said baille to flow thereover.

18. Apparatus for storing and agitating pulp stock comprising, in combination, a storage chest for pulp stock, means for moving pulp stock through said chest, a baiile structure disposed in` the path of movement of said stock and having a deilecting surface against which the stock advances as it moves through the chest, said bale structure provided with means for permitting a portion of said moving stream of pulp stock to pass therethrough and into the area on the side of the baille structure opposite to said surface in order to prevent the accumulation of dead stock in said area.

19. Apparatus for storing and agitating pulp stock comprising a storage chest, a pump communicating With a loW portion of the chest to withdraw pulp stock therefrom, said pump provided With an outlet terminating in a portion extending horizontally over the top of the chest, said horizontally extending portion of the vOutlet being of increasing diameter as its discharge end is approached.

JOHN A. ROSMAIT. 

